Mathematical model of force lubrication systems of agricultural machinery and equipment

Abstract

The service life of engines and transmissions of agricultural machinery and equipment depends on wear intensity of their interacting parts (friction units). In its turn, the wear intensity of friction units is determined by friction losses and heat liberation in them. Optimization of operation of interacting parts and extension of their service life are provided by supply of rational amount of lubricant. Existing calculation methods of oil supply systems are based on the determination of volumetric flows. It is known that in engines, transmissions and hydraulic drives of agricultural machines, the oil is saturated with gas bubbles and gets the physical and chemical properties that differ from the properties of pure oil. That has significant influence on friction losses and heat liberation and causes more intense wear. On the base of the developed mathematical models, the impact of gas bubbles contained in oil on its physical properties (density, viscosity) has been analyzed. The lubrication systems of engines and transmissions of agricultural machinery have been analyzed, their parameters have been determined, including the types of channels of force lubrication systems which significantly influence on the formation of two-phase gas-oil medium. The article proposes the computational dependencies of motion of two-phase gas-oil mixture through the channels of force lubrication systems, which allow to determine rational parameters of channels at the stage of machinery design. That allows to ensure the supply of necessary amount of lubricant for minimization of friction losses, maintaining the required thermal regime of parts and minimization of their wear. Application of suggested mathematical model will allow to decrease the amount of life tests.

Keywords

machine parts / lubrication system / oil density / two-phase gas-oil mixture / cavitation / wear

References

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RIGHTS & PERMISSIONS

Malomyzhev O.L., Fedotova N.E., Medvedeva I.S., Prokop'ev I.S.